Explosion resisting lighting fixture



Aug. 18, 1936. H. P, HAsTlNGs 2,051,479

EXPLOSION RESISTING LIGHTING FIXTURE n Filed Jan. 19, 1934 2Sheets-Sheet 1 Afr l /ll kmv INVENTOR.

ATTORNEYS,

Aug. 18, 1936.

Filed Jan. 19, 1954 2 Sheets-Sheet 2 INVENTOR.

Mu/ @7/ j BY ATTORNEYS,

Patented Aug. 18, 1936 UNITEDA STATES EXPLOSION RESISTING LIGHTINGFIXTURE Harold P. Hastings, Syracuse, N. Y., assgnor to Crouse-HindsCompany, Syracuse, N. Y., a corporation of New York Application January19, 1934, Serial No. 707,293

9 Claims.

This invention relates to lighting units of the explosion resistingtype, particularly intended for use in hazardous places, where there'isthe probability of explosion, if the electrical circuit is made orbroken inthe atmosphere of the location.

y The' invention hasforan object an explosion resisting lighting unitprovided with flame tight joints, the construction being of such naturethat the efficiency of these joints will not be impaired throughordinary use of the lighting unit.

The invention has for a further object the provision of means fordetachably supporting the lamp receptacle in the body` of the unit insuch manner that the lamp compartment yof the unit is effectivelysealed.

The invention has for a further object the provision of meansformaintaining an effective iiame tight joint between the glass globe andthe body of the unit and at the same time permitting relamping of theunit without the necessity of skilled labor or any particular tools. I Afurther and important object of this invention is the provision of meansfor securing the globe to the globe support in iiame tight relationshipthereto, and also to provide for expansion and contraction of the globewithout eiecting the joint.

With the above objects in mind, the invention possesses further noveltyin that its structure is such that the unit can be made in the smallersizes and can be used as an explosion resisting hand lamp, if desired.

Further objects will appear as the description proceeds.

The invention consists in the novel features and in the combinations andconstructions hereinafter set forthand claimed.

InV describing this invention, reference is had to the accompanyingdrawings vin which like chare acters-designate corresponding partsl inall the views. Y

Figure 1 is a sectional view of the unit, partly in elevation, the unitin this instance being provided with a handle for handlamp use.

Figure 2 is a sectional view of the unit provided with means forattaching the same to an electric conduit system.

The invention comprises generally a body, a lamp receptacle supportdetachably secured in the body in such manner as tov provide a ame tightjoint between the support and the body, a globe support detachablysecured to the body and means carried by the globe support fordetachably securing the globe in the support in name tight relationship`thereto and a 4guard separately secured to the support. p

As here shown, the body comprises a casting I0 bell shaped in generalform and being provided with an internally threaded bore I I.` The mouthv5 or open end of theV body Illis threaded'externally at I2. I3designates the receptacle support` and is, as here shown, provided witha depending ange I4 and an upwardly extending annular flange I5, theflange III being threaded externally l0 and the threads beingcomplemental to those of the bore I I of the body, whereby the supportmay be threaded into the body.

A receptacle I6 is secured to the support I3 in any suitable manner, asby screws I 1, the support I3 being provided with passages 'I 8 topermit the service wires to be connected to the socket or lampreceptacle IS. v The upwardly extending ange I5 provides a well whichislled with'suitable sealing compound, after the receptacle I6 20 hasbeen properly wired. The externallythreaded flange I4 provides a ametight joint between the support I3 andthe body I Il and'in conjunctionwith the sealing compound withinV the ange I5 forms an effective sealbetween the lamp compartment of the unit and the upper compartmentthrough which the service wires enter the unit.

It will be understood by those skilled'in the art that a iiamevtightjoint'is a joint which while possibly permitting the passage of gaseswill cool any ignited gases below the ignition `point so that when thegases escape from the unit,v there is no likelihood of igniting theinflammable gases in the atmosphere in which the unit is being used.

The support I3 is secured in the body against 35A becoming loosened 'onaccount'of vibration or otherwiseA by means of the'set screw I9threading through a boss formed on the upper side ofthe support, the endof the screw coacting with the inner Wall of the body, 'as shown inthedrawings. It is to be noted that in the event the receptacle I6, withthe wires 31, 3| connected thereto, becomesin any way defective ordamaged it may be readily removed from the body together with thesupport I3 by backingout the set screw VI9 and uns'crewing the supportI3 Vfrom the body.

As shown in Figure 1, the upper end of the body is truncated andprovided with an opening 20 formed in the inwardly extending iiange 2I.A IOne half, as 22, of the cable clamp yis formed integral with theange 2|, the other portion 23 of the clamp being operated by thelscrews24; The integral portion 22 of the clamp is provided with a groundingscrew 25 to which'the grounding conductor oftthe cable 26-is secured.V.i In thisin'- Y In this unit, andasaseneralrule,inthe hand- Y unitineffective for the purpose fo-rwhich it was stance, where the unit isused as an explosion resisting hand lamp, a handle 21 of rubber or isprovided with a suitable vapor tight bushing Yand cable clamp 30.

slipping the handle 21 back on the cable 26, pass-V ing the end of thecable through the Yripening in the body I0, securing the ends of theconu ductors 3| to the receptacle I6. In lighting units of this type,that is, explosionresistingtype, the service wires or leads arevgenerallysoldered or permanently secured to the terminals in the lampreceptacle. ,This is to avidany? possibility. Yof loose connections.VAfter the conductors 3| have been properly secured to the receptacle I6,the receptacle ls .seeuredtothezsupport I3 and :the support screwed intothe body, The ground Yconductor 32 maythen besecured under the screwVZifand the handle 21 secured to the ilange 2| and .thebushingtightened.. n

VReferring Vto Figure 2 vof the drawings, the

- upper end. Aof the housing is provided with Ya threaded passage to:receive the threadedxend of a conduit enclosing the service-wires; Anopening is provided in one side of the bodyadiacent its Vupper end and aclosure or plug v36 threaded into the opening. In wiriu'gfths unit, :theleads ,31. from the receptacle IiiV and the Service Wires, not shown;are broughtv outthrough the 'side opening in the housing, properlyconnected andreturned through the openinsinto'the upper Cham@- ber of,the body. It it becomes necessarytoreplace thelreceptacle I6 Vin thisunit, the leads 31 are disconnected `from the/service wires andthereceptacle ,support I3 is V,unser@awed Vfrom the body.

Ylamp unit shown in Figure 1, the yreceptacle I6 yis provided withleads, andthe receptacle is secured to the supportand the ,sealingcompound `run into the well .above the support at the factory. renderingit only necessary for the unskilled workerin charge of the units tounserew the support I3, if necessary .to replace the receptacle, and

to again screw intothe-support and receptacle, thus Vpreventingthepossibility of rendering the intended, .by destroying the seals of thelamp compartment. Y f

The globe 4070i the `fixture which defines the lower portion of thelampcorn-partment isCMrled by a Vglobe Vsupport whichV isdetachablysecured .to the loweror open end of the housing l0, As hereV shown, the:support 4I is cylindrical and provided with an inwardly extendingflange 42 at its lower end,` the cylindrical portion .being internallythreaded, andthe threads being coinplemental to the externally threadedportion I2 of the bod-y Ill.,V 'The .supportlI `also carriesa guard -43whioh'ls here'rshown as detachably -secured VVto the support by vmeans`of screws 44,

' although, obviously, the support 4 I andthe guard is llstuifllyA .ofleader suitable resilient metallic Y material. ',Ihe ange 45 of theglobe is" somewhat less'in Vdiameter than Vthe bore of the support 4 I:and extends upwardly Vand inwardly, providing Y Va space 4l `which islled with a suitablesealing cl'irnpound. preferably .fa compound which.will

This unitmay be wiredfby remain plastic at ordinary temperatures. Anexternally threaded ring or washer 48 is screwed into the support 4I andseats against the sealing compound. It will be observed that thisstructure secures the globe to the globe support in such manner as toprevent the escape'of any ignited gases from within the globe, and atthe same time permits ready removal of the globe from the support if the'necessity arises, and alsoV permits expansion and contraction of theouter 'or open end of the globe. VInasm'uch -asthis unit is totallyenclosed, and particularly in units of the'smaller size as here shown,the lamp produces an appreciable amount of heat which resultsinconsiderable vexpansion of the globe 40. lnasmuch as these units mustwithstand a mine Y imum amount of pressure, usually five hundredkpoundsper square inch, it is very important that the glassY globes arenot placed under an initial 'strain as they would be materiallyweakened. kA

globe cools off it contracts andthe yflame/tight joint is stillestablished by the plastic compound.

AVA screw 49 is carriedbythe kbody and arranged to form a lock toprevent `unintentibnal removal of the support 4I `rfrom the body.A Asshown lin Figure 1, the guard is provided with a-suitable hook 59 topermit theunit to be suspended from the -outer end, and `in Figure 2,1.a shade 5I' may be provided, which is secured to the globe support 4|,and :as shown, i clamped between the guard 43 and the support 4I.It'will be observed that thesev units may -be relampedv by simplyloosening the screw 49 and unscrewng the support or globe and guardunitirom thebodywith` out, in any manner',- aiecting the joint betweenthe globe and the globe support. However, While the globe and guard unitare secured to the body,` it is impossible to remove the globe from' theglobe support.

The arrangement of this structure the structure of the receptaclesupport Yis to provide a means. whereby the fixture may be maintained byan unskilled .operator without disturbing the flame tightjointY .oftheunit, which requires some skill, or at leastsome appreciationV o f itsvalue. The globe and support are assembled at thoractory and in theevent the globe becomes damaged, a new globey unit is provided,permitting the damaged unit to be returned to the factoryrfor reeconditioning by proper persons. i

WhatIclaim-is: ,Y Y; f' i l. An explosion resisting lighting unitincluding a body having an internally 'threaded bore, and an externallythreaded annular "flange, a receptacle support provided withexternal'threads complemental to the threads inthe body,a re;V ceptacle-carriedby saidsupport,V a globeand Y l guard unit provided withinternal threads com# plemental tothe external threadson the annularflange, a globe and a guard carried by said i unit,rand ahandle rdetachably 'secured to theopposite end of the body. Y Y l l g 2. Anexplosion Yresisting lighting unit including a body open at its ends andhaving` an internally threaded bore, 'a ikreceptaclelsupport 'threadedinto said'bore,and a receptacle vcarried bythe receptacle support, aglobe 'supportde-l carried by .the globe Support, .andi-means fordetachably securing the globe in said support and forming a flame tightjoint between the globe and the support, and a handle secured to theopposite end of the body and forming a closure therefor.

3. An explosion proof lighting unit comprising a body, a receptaclesupport, means for detachably securing said support in the body, a flametight joint between the body and the support, a globe support, a globecarried by the support and self-contained therewith, a flame prooi jointbetween the globe and the globe support including an expansible andcontractile plastic packing ring between the globe and its support andcapable of expanding and contracting and maintaining the joint duringdifferent degrees of temperature, and means for detachably securing theglobe support to the body and forming a flame proof joint between theglobe support and the body.

4. An explosion proof lighting unit comprising a body, a receptaclesupport, means for detachably securing said support in the body, a iametight joint between the body and the support, a globe support, a globecarried by the support and self-contained therewith, a ilame tight jointbetween the globe and the globe support including an expansible andcontractile packing ring and capable of expanding and contracting andmaintaining the joint during diierent degrees of temperature, the globehaving an annular bead tapering toward the inner end of the globeforming a space V-shaped in cross section between the bead and the globesupport, the expansible and contractile packing filling said V-shapedspace, and means for detachably securing the globe support to the bodyand forming a flame proof joint between the globe support and the body.

5. An explosion proof lighting unit comprising a body, a receptaclesupport, means for detachably securing said support in the body, a ilametight joint between the body and the support, a globe support, a globecarried by the support and selfcontained therewith, a flame tight jointbetween the globe and the globe support including a plastic expansibleand contractile packing ring between the globe and its support andcapable of expanding and contracting and maintaining the joint duringdifferent degrees of temperature, the v globe having an annular beadtapering toward the inner end of the globe forming a space V- shaped incross section between the bead and the globe support, the expansible andcontractile packing lling said V-shaped space, resilient means forretaining the expansible and contractile packing in said space, andmeans for detachably securing the globe support to the body and forminga flame proof joint between the globe support and the body.

6. An explosion proof lighting unit comprising a body, a receptaclesupport, means for detachably securing said support in the body, a ametight joint between the body and the support, a globe support, a globecarried by the support and self-contained therewith, a ame tight jointbetween the globe and the globe support including an expansible andcontractile packing ring between the globe and its support and capableof expanding and contracting and maintaining the joint during differentdegrees of temperature, the globe forming a space V-shaped in crosssection between the bead and the globe support, the expansible andcontractile packing filling said V- shaped space, a resilient metallicwasher between the globe and its support and arranged to cover saidV-shaped space and arranged to permit radial expanding and contractingmovements of the globe and retain the expansible and contractile packingin said space, and means for detachably securing the globe support tothe body and forming a ame proof joint between the globe support and thebody.

7. An explosion resisting lighting unit comprising a bell shaped bodyhaving an internally threaded bore, a receptacle support threaded insaid bore and dividing the body into a service compartment and a lampcompartment, said support being provided on one side with a well to'receive sealing compound, and a receptacle mounted on the other side ofsaid support and extending into the lamp compartment, and a globe andguard unit detachably secured to the body.

8. An explosion resisting lighting unit comprising a bell shaped bodyopen at each end and having an internally threaded bore adjacent thelarge end, a receptacle support threading into said bore and dividingthe body into a service compartment, and a lamp compartment, areceptacle mounted on said support and extending into the lampcompartment and being provided with a well for receiving sealingcompound, a globe and guard unit detachably secured to the large end ofthe body, the smaller end of the body being provided with a cable grip,and a handle detachably secured to the smaller end of the body andforming a closure for the opening therein.

9. An explosion resisting lighting unit comprising a body having aninternally threaded bore, a

receptacle support threaded in said bore and dividing the body into aservice compartment and a lamp compartment, and eiecting a ame tightseal between said compartments, a lamp receptacle mounted on one side ofsaid support and extending into the lamp compartment, and a globe andguard unit detachably secured to the body.

HAROLD P. HASTINGS.

